基于组合函数的脚踝康复机器人轨迹规划

Combined function based trajectory planning for a novel ankle rehabilitation robot

针对所设计的混联式脚踝康复机器人的轨迹规划问题,对该机构并联部分的运动学逆解、轨迹规划方法、推杆输出控制进行了研究,提出了一种摆线函数和矩形函数相组合的康复轨迹,推导了其加速度、速度和位移的解析表达式。对比分析了该组合轨迹函数和传统摆线形式的轨迹函数对脚踝康复机构运动启停平稳性、最大速度、最大加速度以及刚性冲击的影响;最后,根据运动学逆解,计算了康复机构作跖屈/背屈运动时各推杆的输出量,并将其导入ADAMS进行了仿真实验,探讨了不同组合函数下各推杆的运动参数以及末端参考点的运动轨迹。研究结果表明:采用组合函数形式轨迹的新型混联式脚踝康复机器人能为患者提供一种启停平稳性较好,最大速度/加速度小、刚性冲击较小的康复运动。

Aiming at the trajectory planning problems of the proposed hybrid ankle rehabilitation robot,the inverse kinematics,trajectory planning and the displacement of the pushrods were analyzed. A new trajectory for a novel patented ankle rehabilitation robot was proposed,which is composed of a cycloid function and a rectangular function. The kinetic characteristics i. e.,the acceleration,the velocity and the displacement of the trajectory were derived and compared with those of a traditional cycloid trajectory. The influences of two types of trajectories on the stability,the maximum speed,the maximum acceleration and the rigid impact of the rehabilitation robot were compared. Finally,an inverse kinematic analysis was conducted to yield the displacements of three pushrods in the rehabilitation robot when it takes a planter/dorsal flexion motion. The displacements of three pushrods were imported into the ADAMS to analyze the parameters of the pushrods and the trajectory of the reference point. The results indicate that the proposed combined function based trajectory can provide a rehabilitation motion with better stability and less impact on the ankle.